Method of curing gelatinous material stock



Patented Jan. 26, 1943 METHOD OF CURING GELATINOUS MATE- RIAL STOCK Edward F. Christopher, Chicago, Ill., assignor to Industrial Patents Corporation, Chicago, 11]., a

corporation of Delaware No Drawing. Application December 24, 1938, Serial No. 247,706

21 Claims. (Cl. 260-118) I This invention relates to a method of extracting gelatinous material from gelatinous material stock such as hide trimmings, fleshings, sinews, and the like.

One of the objects of this invention is to provide a method of treating gelatinous material stock to yield a high test gelatinous material.

Another object of this invention is to provide a method of curing gelatinous material stock such as hide trimmings, fleshings, sinews, and the like to shorten the curing period.

Further objects and advantages will be apparent from the description and the claims which follow.

The present invention contemplates the treatment of gelatinous material stock with an alkaline solution of a water soluble salt of a metal whose oxide or hydroxide is soluble in excess alkali and whose salts are not precipitants for gelatinous material.

The term gelatinous material stock is used herein and it is to be understood to designate animal waste matter such as shouts, lips, ears, hide trimmings, fieshings, sinews, and the like. The term gelatinous material is used herein and is to be understood to designate all grades of animal gelatin and glue including those intermediate products commonly known as low grade gelatin and high grade glue.

In the conventional practice of extracting gelatinous material from gelatinous material stock, the stock is cured in a lime bath. The curing period requires from four to twelve weeks depending on the type of stock, the temperatures,

and the amount of caustic which is generally employed to fortify the lime. The cured stock is then thoroughly washed and the pH is adjusted by the addition of acid. The stock is then transferred to cooking vessels and the gelatinous material extracted with water.

In curing gelatinous material stock according to my invention, the stock is placed in a dilute alkaline solution containing a small amount of a water soluble salt of the type described. After several days the stock is cured and the alkaline solution is then drained from the stock. The stock is then washed with water and the pH is adjusted by the addition of acid. The stock is then transferred to the cooking vessels and the gelatinous material extracted with water. In the practice of my invention, it is possible to recover the hair which may be present on this type of stock in a clean condition at the end of the curring period, whereas the conventional lime process does not permit a recovery of the hair.

Caustic soda, caustic potash, or ammonium hydroxide solutions are examples of alkaline solutions which may be employed in the practice of my invention. I have found that I may employ alkali solutions of various concentrations, 0.025 normal to 1.5 normal solutions of these alkalis being satisfactory.

Water soluble salts of aluminum, copper, tin, and zinc are examples of suitable metallic salts. Sodium zincate, sodium stannite, sodium stannate, and sodium aluminate are satisfactory for the purposes of this invention. In practicing the invention with caustic soda, for example, the addition of the salts of aluminum, tin, or zinc to caustic soda results in the formation of the aluminate, stannate, stannite, or zincate.

I have found that from 0.5 per cent to 10 per cent metallic salt, based upon the weight of the stock which is being treated, is generally satisfactory in curing the gelatinous material stock.

Hide trimmings, for example, after being soaked in an alkaline solution containing a small amount of the metallic salt may be dehaired after several days. The dehaired stock is then washed with water to remove the reagents which may adhere to the surface of the stock and to remove other materials which may have been released during the curing period.

The treatment with the alkaline solution of the metallic salt and subsequent washing effects a removal or precipitation of the adulterants and diluents. These inert substances such, as blood and certain albuminous materials, if not removed or precipitated, may be extracted along with the gelatinous material, thereby adversely aifecting the quality of the gelatinous material.

The washed stock is then treated with acid to adjust the stock to the proper pH, after which the stock is transferred to open cooking kettles for the extraction of the gelatinous material. The gelatinous material may be extracted in any manner, for example by cooking in open kettles in successive steps, the temperature in each step being increased. The resulting solution containing the gelatinous material is then concentrated, chilled, and dried in any conventional manner.

I have found that in the curing of fresh pork skin trimmings, caustic soda solutions containing from 0.1 per cent to 2 per cent excess caustic I soda, about 0.025 normal to about 0.5 normal solution, and from about 1 per cent to 10 per cent sodium stannite, sodium zincate, or sodium aluminate, based upon the weight of the stock being treated, are quite satisfactory. I

Fresh pork skin trimmings may be cured in higher, in some cases being twice that ofgelatinous material prepared by other processes.

In curing gelatinous material such as snouts, lips, and ears, solutions containing from 0.25 per cent to 2.5 per cent free caustic soda, about 0.05 normal to about 0.65 normal solutions, and from 2.5 per cent to per cent sodium zincatehave been found to be very satisfactory. Glue may be prepared from this type of stock by a four day curing period.

Water soluble salts of aluminum, tin, and zinc in amounts of from about 0.5 per cent to 10 per cent, based upon the weight of the stock to be cured, for example aluminum sulphate, stannous chloride, aluminum chloride, zinc oxide, or zinc sulphate may be added to a caustic alkali solution to form the aluminate, stannite, or zincate.

It is to be understood that the range of concentrations and the specific concentrations of the alkaline solutions and the salts set forth herein are preferred concentrations. The upper limit of concentration of the alkali is dependent upon the particular type of stock to be cured. The concentration of alkali should not be so high that the stock becomes softened or disintegrated to such an extent as to prevent handling of the cured stock in the subsequent extraction of the gelatinous material. The curing period may be varied to some extent by varying the concentration of the constituents of the curing bath and by varying thetemperatures.

"My process greatly reduces the time of curing, and thereby reduces the large storage space and the large'number of curing pits which are ordinarily necessary in the manufacture of gelatinous material from this type of stock. The curing period will vary with a fixed curing bath,

dependent upon the particular type of stock being treated. For example, fresh pork skin trimmings may be cured in from sixteen hours to forty-eight hours, whereas snouts, lips, and ears "may require a curing period of four or five days.

I claim: 1. The method of preparing gelatinous material from gelatinous material stock which comprises curing the stock in an alkaline solution of a substance selected from the group consisting of Watersoluble salts of metals whose oxides are soluble in excess alkali and water soluble salts of metals" whose hydroxides are soluble in excess alkalL'separ'ating the solution-from the stock, and thereafter extracting the gelatinous the amount of water soluble salt being based 'upon the Weight of the stock, separating the alkaline solution from the stock, and thereafter extracting the 1 gelatinous treated stock. v p

3. The method of preparing gelatinous matematerial from the rial from gelatinous material stock which com prises treating the stock with an 0.025 normal to 1.5 normal alkaline solution containing from 0.5 per cent to 10 per cent of a substance selected from the group consisting of water soluble salts of metals whose oxides are soluble in excess alkali and water soluble salts of metals whose hydroxides are soluble in excess alkali, the amount of water soluble salt being based upon the weight of the stock, separating the alkaline solution from the stock, and thereafter extracting the gelatinous material from the treated stock.

4. The method of preparing gelatinous material 'f'rom gelatinous material stock which comprises treating the stock with an 0.025 normal to 1.5 normal caustic soda solution containing from 0.5 per cent to 10 per cent of a substance selected from the group consisting of water soluble salts of metals whose oxides are soluble in excess alkali and water soluble salts of metals whose hydroxides are soluble in excess alkali, the amount of water soluble salt being based upon the weight of the stock, separating the alkaline solution from the stock, and thereafter extracting the gelatinous material from the treated stock.

5. The method of preparing gelatinous material from gelatinous material stock which comprises treating the stock with an 0.025 normal to 1.5 normal caustic soda solution containing from 0.5 per cent to 10 per cent sodium stannite, the amount of sodium stannite being based upon the weight of the stock separating the alkaline solution from the stock, and thereafter extracting the gelatinous material from the treated stock.

6. The method of preparing gelatinous material irom gelatinous material stock whichgcomprises soaking the stock in an 0.025 normal to 1.5 normal caustic soda solution containing from 0.5 per cent to 10 per cent sodium zincate, the amount of sodium zincate beingbased. upon the weight of the. stock, separating the alkalinesolution from the stock, and thereafter extracting ie gelatinous material from the treated stock.

7. The method of preparing gelatinous material from gelatinous material stock which comprises soaking the stock in an 0.025 normal to 1.5 normal caustic soda solution containing from 0.5 per cent to 10 per cent sodium alum-inate, the amount of sodium aluminate being based upon the weight of the stock, separating the alkaline solution from the stock, and thereafter extracting the gelatinous material from the treated stock.

3. The method of curing gelatinous material stock which comprises soaking the stock in an alkaline solution of a substance selected from the group consisting of Water, soluble salts of metals whose oxides are soluble in eXcessj alkali and water soluble salts of metals whose hydroxides are soluble in excess. alkali. 1

9. The method of curing, gelatinous material stock which comprises treating the stock Withan 0.025 normal to 1.5 normal alkaline solution containing from 0.5 per cent to 10 per centof a substance selected from thegrouplconsisting of Water soluble salts of metals whose oxides are soluble in excess alkali and water 'solublesalts of metals Whose hydroxides aresoluble in excess alkali, the amount of Water soluble salt being based upon the weight of the stock.

10. The method of curing gelatinous material stock which comprises treating the stock with an 0.025 normal to 1.5 normal caustic soda solution containing from 0.5per cent to 10 er' cent or a substance selected from the group consisting of water soluble salts of metals whose oxides are soluble in excess alkali and water soluble salts of metals whose hydroxides are soluble in excess alkali, the amount of water soluble salt being based upon the weight of the stock.

11. The method of curing gelatinous material stock which comprises treating the stock with an 0.025 normal to 1.5 normal caustic soda solution containing from 0.5 per cent to per cent sodium stannite, the amount of sodium stannite being based upon the weight of the stock.

12. The method of curing gelatinous material stock which comprises treating the stock with an 0.025 normal to 1.5 normal caustic soda solution containing from 0.5 per cent to 10 per cent sodium zincate, the amount of sodium zincate being based upon the weight of the stock.

13. The method of curing gelatinous material stock which comprises treating the stock with an 0.025 normal to 1.5 normal caustic soda solution containing from 0.5 per cent to 10 per cent sodium aluminate, the amount of sodium aluminate being based upon the weight of the stock.

14. The method of preparing gelatinous material from gelatinous material stock which comprises treating the stock with a dilute caustic potash solution containing a small amount of a substance selected from the group consisting of water soluble salts of metals whose oxides are soluble in excess alkali and water soluble salts of metals whose hydroxides are soluble in excess alkali, the amount of water soluble salt bein based upon the weight of the stock, separating the alkaline solution from the stock, and thereafter extracting the gelatinous material from the stock.

15. The method of preparing gelatinous material from gelatinous material stock which comprises treating the stock with a dilute solution of ammonium hydroxide containing a small amount of a substance selected from the group consisting of water soluble salts of metals whose oxides are soluble in excess alkali and water soluble salts of metals whose hydroxides are soluble in excess alkali, the amount of Water soluble salt being based upon the Weight of the stock, separating the alkaline solution from the stock, and thereafter extracting the gelatinous material from the stock.

16. The method of curing gelatinous material stock which comprises treating the stock with a dilute caustic potash solution containing a small amount of a substance selected from the group consisting of water soluble salts of metals whose oxides are soluble in excess alkali and water soluble salts of metals whose hydroxides are soluble in excess alkali, the amount of water soluble salt being based upon the weight of the stock.

17. The method of curing gelatinous material stock which comprises treating the stock with a dilute solution of ammonium hydroxide containing a small amount of a substance selected from the group consisting of water soluble salts of metals whose oxides are soluble in excess alkali and water soluble salts of metals whose hydroxides are soluble in excess alkali, the amount of water soluble salt being based upon the weight of the stock.

18. The method of preparing gelatinous material from gelatinous material stock which comprises preparing a caustic soda solution, adding suflicient zinc oxide to the caustic soda solution to form from 0.5 per cent to 10 per cent sodium zincate, the amount of caustic soda being sumcient to form an 0.025 normal to 1.5 normal caustic soda solution of the zincate, the amount of sodium zincate being based upon the weight of the stock to be treated, soaking the stock in the caustic soda solution containing sodium zincate, separating the solution from the stock, and thereafter extracting the gelatinous material from the treated stock.

19. The method of preparing gelatinous material from gelatinous material stock which comprises preparing a caustic soda solution, adding sufficient zinc sulphate to the caustic solution to form from 0.5 per cent to 10 per cent sodium zincate, the amount of caustic soda being sufficient to form an 0.025 normal to 1.5 normal caustic soda solution of the zincate, the amount of sodium zincate being based upon the weight of the stock to be treated, soaking the stock in the caustic soda solution containing sodium zincate, separating the solution from the stock, and thereafter extracting the gelatinous material from the treated stock.

20. The method of curing gelatinous material stock which comprises preparing a caustic soda solution, adding sufficient zinc oxide to the caustic solution to form from 0.5 per cent to 10 per cent sodium zincate, the amount of caustic soda being sufficient to form an 0.025 normal to 1.5 normal caustic soda solution of the zincate, the amount of sodium zincate being based upon the weight of the stock to be cured, and treating the stock with the caustic soda solution containing the sodium zincate.

21. The method of curing gelatinous material stock which comprises preparing a caustic soda solution, adding sufficient zinc sulphate to the caustic solution to form from 0.5 per cent to 10 per cent sodium zincate, the amount of caustic soda being sufficient to form an 0.025 normal to 1.5 normal caustic soda solution of the zincate, the amount of sodium zincate being based upon the weight of the stock to be cured, and treating the stock with the caustic soda solution containing sodium zincate.

EDWARD F. CHRISTOPHER. 

